The primary goal of this proposal is to examine the relationship between history of overweight/obesity and smoking in young adult women from genetic and epidemiologic perspectives. Smoking and overweight/obesity are heritable, but modifiable, risk factors for cardiovascular disease in their own rights, but the combination of the two in the same individual can have a synergistic effect on the risk of morbidity and mortality. Data from 3787 European/other Ancestry (EA) and African American (AA) members of the Missouri Adolescent Female Twin Study (MOAFTS) will be used to address three aims. First, discrete time survival analysis will be used to examine the relationship between overweight/obesity and the initiation and progression of smoking (initial use, regular use, dependence and cessation) in young AA and EA women to identify relevant mediators and/or moderators, particularly history of childhood sexual molestation, early maturation and major depression. Next, the degree of correlation of genetic and environmental risk between overweight/obesity and smoking initiation and progression and the possibility that overweight/obesity moderates the genetic influences on smoking initiation and progression will be assessed using multivariate twin modeling techniques. Finally, the methods described above will be used again to examine the relationship between overweight/obesity and the initiation and progression of smoking from a longitudinal perspective in a sub sample of women who had not yet begun to smoke regularly at the baseline assessment. Results from this research will provide insight into the reasons for the co-occurrence of smoking and overweight/obesity in young women and could lead to the development of new interventions to reduce the prevalence of these risk factors and ultimately lead to a reduction in related morbidity and mortality. [unreadable] [unreadable] Relevance to Public Health: The Think Tank on Enhancing Obesity Research at the National Heart, Lung and Blood Institute has listed the study of "the relationships between BMI or adiposity phenotypes and cardiovascular and pulmonary disease risk factors and events among ethnic groups" as a key research recommendation. Smoking and obesity are both important heart disease risk factors, and in combination they can be particularly deadly. Therefore, it is important to better understand the relationship between smoking and obesity. Identification of common risk factors will aid in the development of interventions that can target both of these important risk factors for morbidity and mortality. [unreadable] [unreadable] [unreadable] [unreadable]